foxy beret - 3 strands?

hello... i have the foxy beret pattern and i have 2 skeins of yarn (as per pattern), but it says to knit with 3 strands. i'm not sure how to do this from 2 balls. any ideas? i'm a newish knitter and tried to find an online tutorial but alas no. do i just need to get a 3rd ball? or perhaps i unravel 1. ???? thanks.